[PATCH 28/39] scsi: reintroduce scsi_driver.init_command

Christoph Hellwig
2014-03-17T13:31:36Z

[-- Attachment #1: 0028-scsi-reintroduce-scsi_driver.init_command.patch --]
[-- Type: text/plain, Size: 11749 bytes --]

Instead of letting the ULD play games with the prep_fn move back to
the model of a central prep_fn with a callback to the ULD. This
already cleans up and shortens the code by itself, and will be required
to properly support blk-mq in the SCSI midlayer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/scsi/scsi_lib.c | 66 ++++++++++++++++++++++++++------------------
drivers/scsi/sd.c | 46 +++++++++++-------------------
drivers/scsi/sr.c | 19 ++++---------
include/scsi/scsi_driver.h | 8 ++----
4 files changed, 63 insertions(+), 76 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a23e8c3..9889c75 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -470,6 +470,16 @@ void scsi_requeue_run_queue(struct work_struct *work)
scsi_run_queue(q);
}

+static void scsi_uninit_command(struct scsi_cmnd *cmd)
+{
+ if (cmd->request->cmd_type == REQ_TYPE_FS) {
+ struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
+
+ if (drv->uninit_command)
+ drv->uninit_command(cmd);
+ }
+}
+
/*
* Function: scsi_requeue_command()
*
@@ -494,6 +504,8 @@ static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
struct request *req = cmd->request;
unsigned long flags;

+ scsi_uninit_command(cmd);
+
spin_lock_irqsave(q->queue_lock, flags);
blk_unprep_request(req);
req->special = NULL;
@@ -1078,15 +1090,7 @@ static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,

int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
{
- struct scsi_cmnd *cmd;
- int ret = scsi_prep_state_check(sdev, req);
-
- if (ret != BLKPREP_OK)
- return ret;
-
- cmd = scsi_get_cmd_from_req(sdev, req);
- if (unlikely(!cmd))
- return BLKPREP_DEFER;
+ struct scsi_cmnd *cmd = req->special;

/*
* BLOCK_PC requests may transfer data, in which case they must
@@ -1130,15 +1134,11 @@ EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
*/
int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
{
- struct scsi_cmnd *cmd;
- int ret = scsi_prep_state_check(sdev, req);
-
- if (ret != BLKPREP_OK)
- return ret;
+ struct scsi_cmnd *cmd = req->special;

if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
&& sdev->scsi_dh_data->scsi_dh->prep_fn)) {
- ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
+ int ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
if (ret != BLKPREP_OK)
return ret;
}
@@ -1148,16 +1148,13 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
*/
BUG_ON(!req->nr_phys_segments);

- cmd = scsi_get_cmd_from_req(sdev, req);
- if (unlikely(!cmd))
- return BLKPREP_DEFER;
-
memset(cmd->cmnd, 0, BLK_MAX_CDB);
return scsi_init_io(cmd, GFP_ATOMIC);
}
EXPORT_SYMBOL(scsi_setup_fs_cmnd);

-int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
+static int
+scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
{
int ret = BLKPREP_OK;

@@ -1209,9 +1206,9 @@ int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
}
return ret;
}
-EXPORT_SYMBOL(scsi_prep_state_check);

-int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
+static int
+scsi_prep_return(struct request_queue *q, struct request *req, int ret)
{
struct scsi_device *sdev = q->queuedata;

@@ -1242,18 +1239,33 @@ int scsi_prep_return(struct request_queue *q, struct request *req, int ret)

return ret;
}
-EXPORT_SYMBOL(scsi_prep_return);

-int scsi_prep_fn(struct request_queue *q, struct request *req)
+static int scsi_prep_fn(struct request_queue *q, struct request *req)
{
struct scsi_device *sdev = q->queuedata;
- int ret = BLKPREP_KILL;
+ struct scsi_cmnd *cmd;
+ int ret;

- if (req->cmd_type == REQ_TYPE_BLOCK_PC)
+ ret = scsi_prep_state_check(sdev, req);
+ if (ret != BLKPREP_OK)
+ goto out;
+
+ cmd = scsi_get_cmd_from_req(sdev, req);
+ if (unlikely(!cmd)) {
+ ret = BLKPREP_DEFER;
+ goto out;
+ }
+
+ if (req->cmd_type == REQ_TYPE_FS)
+ ret = scsi_cmd_to_driver(cmd)->init_command(cmd);
+ else if (req->cmd_type == REQ_TYPE_BLOCK_PC)
ret = scsi_setup_blk_pc_cmnd(sdev, req);
+ else
+ ret = BLKPREP_KILL;
+
+out:
return scsi_prep_return(q, req, ret);
}
-EXPORT_SYMBOL(scsi_prep_fn);

/*
* scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 470954a..33e349b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -109,6 +109,8 @@ static int sd_suspend_system(struct device *);
static int sd_suspend_runtime(struct device *);
static int sd_resume(struct device *);
static void sd_rescan(struct device *);
+static int sd_init_command(struct scsi_cmnd *SCpnt);
+static void sd_uninit_command(struct scsi_cmnd *SCpnt);
static int sd_done(struct scsi_cmnd *);
static int sd_eh_action(struct scsi_cmnd *, int);
static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
@@ -503,6 +505,8 @@ static struct scsi_driver sd_template = {
.pm = &sd_pm_ops,
},
.rescan = sd_rescan,
+ .init_command = sd_init_command,
+ .uninit_command = sd_uninit_command,
.done = sd_done,
.eh_action = sd_eh_action,
};
@@ -838,9 +842,9 @@ static int scsi_setup_flush_cmnd(struct scsi_device *sdp, struct request *rq)
return scsi_setup_blk_pc_cmnd(sdp, rq);
}

-static void sd_unprep_fn(struct request_queue *q, struct request *rq)
+static void sd_uninit_command(struct scsi_cmnd *SCpnt)
{
- struct scsi_cmnd *SCpnt = rq->special;
+ struct request *rq = SCpnt->request;

if (rq->cmd_flags & REQ_DISCARD) {
free_page((unsigned long)rq->buffer);
@@ -853,18 +857,10 @@ static void sd_unprep_fn(struct request_queue *q, struct request *rq)
}
}

-/**
- * sd_prep_fn - build a scsi (read or write) command from
- * information in the request structure.
- * @SCpnt: pointer to mid-level's per scsi command structure that
- * contains request and into which the scsi command is written
- *
- * Returns 1 if successful and 0 if error (or cannot be done now).
- **/
-static int sd_prep_fn(struct request_queue *q, struct request *rq)
+static int sd_init_command(struct scsi_cmnd *SCpnt)
{
- struct scsi_cmnd *SCpnt;
- struct scsi_device *sdp = q->queuedata;
+ struct request *rq = SCpnt->request;
+ struct scsi_device *sdp = SCpnt->device;
struct gendisk *disk = rq->rq_disk;
struct scsi_disk *sdkp;
sector_t block = blk_rq_pos(rq);
@@ -886,12 +882,6 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
} else if (rq->cmd_flags & REQ_FLUSH) {
ret = scsi_setup_flush_cmnd(sdp, rq);
goto out;
- } else if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
- ret = scsi_setup_blk_pc_cmnd(sdp, rq);
- goto out;
- } else if (rq->cmd_type != REQ_TYPE_FS) {
- ret = BLKPREP_KILL;
- goto out;
}
ret = scsi_setup_fs_cmnd(sdp, rq);
if (ret != BLKPREP_OK)
@@ -903,11 +893,10 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
* is used for a killable error condition */
ret = BLKPREP_KILL;

- SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
- "sd_prep_fn: block=%llu, "
- "count=%d\n",
- (unsigned long long)block,
- this_count));
+ SCSI_LOG_HLQUEUE(1,
+ scmd_printk(KERN_INFO, SCpnt,
+ "%s: block=%llu, count=%d\n",
+ __func__, (unsigned long long)block, this_count));

if (!sdp || !scsi_device_online(sdp) ||
block + blk_rq_sectors(rq) > get_capacity(disk)) {
@@ -1127,7 +1116,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
*/
ret = BLKPREP_OK;
out:
- return scsi_prep_return(q, rq, ret);
+ return ret;
}

/**
@@ -1663,6 +1652,8 @@ static int sd_done(struct scsi_cmnd *SCpnt)
unsigned char op = SCpnt->cmnd[0];
unsigned char unmap = SCpnt->cmnd[1] & 8;

+ sd_uninit_command(SCpnt);
+
if (req->cmd_flags & REQ_DISCARD || req->cmd_flags & REQ_WRITE_SAME) {
if (!result) {
good_bytes = blk_rq_bytes(req);
@@ -2872,9 +2863,6 @@ static void sd_probe_async(void *data, async_cookie_t cookie)

sd_revalidate_disk(gd);

- blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
- blk_queue_unprep_rq(sdp->request_queue, sd_unprep_fn);
-
gd->driverfs_dev = &sdp->sdev_gendev;
gd->flags = GENHD_FL_EXT_DEVT;
if (sdp->removable) {
@@ -3021,8 +3009,6 @@ static int sd_remove(struct device *dev)
scsi_autopm_get_device(sdkp->device);

async_synchronize_full_domain(&scsi_sd_probe_domain);
- blk_queue_prep_rq(sdkp->device->request_queue, scsi_prep_fn);
- blk_queue_unprep_rq(sdkp->device->request_queue, NULL);
device_del(&sdkp->dev);
del_gendisk(sdkp->disk);
sd_shutdown(dev);
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 40d8592..93cbd36 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -79,6 +79,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
static DEFINE_MUTEX(sr_mutex);
static int sr_probe(struct device *);
static int sr_remove(struct device *);
+static int sr_init_command(struct scsi_cmnd *SCpnt);
static int sr_done(struct scsi_cmnd *);
static int sr_runtime_suspend(struct device *dev);

@@ -94,6 +95,7 @@ static struct scsi_driver sr_template = {
.remove = sr_remove,
.pm = &sr_pm_ops,
},
+ .init_command = sr_init_command,
.done = sr_done,
};

@@ -378,21 +380,14 @@ static int sr_done(struct scsi_cmnd *SCpnt)
return good_bytes;
}

-static int sr_prep_fn(struct request_queue *q, struct request *rq)
+static int sr_init_command(struct scsi_cmnd *SCpnt)
{
int block = 0, this_count, s_size;
struct scsi_cd *cd;
- struct scsi_cmnd *SCpnt;
- struct scsi_device *sdp = q->queuedata;
+ struct request *rq = SCpnt->request;
+ struct scsi_device *sdp = SCpnt->device;
int ret;

- if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
- ret = scsi_setup_blk_pc_cmnd(sdp, rq);
- goto out;
- } else if (rq->cmd_type != REQ_TYPE_FS) {
- ret = BLKPREP_KILL;
- goto out;
- }
ret = scsi_setup_fs_cmnd(sdp, rq);
if (ret != BLKPREP_OK)
goto out;
@@ -517,7 +512,7 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
*/
ret = BLKPREP_OK;
out:
- return scsi_prep_return(q, rq, ret);
+ return ret;
}

static int sr_block_open(struct block_device *bdev, fmode_t mode)
@@ -718,7 +713,6 @@ static int sr_probe(struct device *dev)

/* FIXME: need to handle a get_capabilities failure properly ?? */
get_capabilities(cd);
- blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
sr_vendor_init(cd);

disk->driverfs_dev = &sdev->sdev_gendev;
@@ -993,7 +987,6 @@ static int sr_remove(struct device *dev)

scsi_autopm_get_device(cd->device);

- blk_queue_prep_rq(cd->device->request_queue, scsi_prep_fn);
del_gendisk(cd->disk);

mutex_lock(&sr_ref_mutex);
diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
index 20fdfc2..b507729 100644
--- a/include/scsi/scsi_driver.h
+++ b/include/scsi/scsi_driver.h
@@ -6,15 +6,14 @@
struct module;
struct scsi_cmnd;
struct scsi_device;
-struct request;
-struct request_queue;
-

struct scsi_driver {
struct module *owner;
struct device_driver gendrv;

void (*rescan)(struct device *);
+ int (*init_command)(struct scsi_cmnd *);
+ void (*uninit_command)(struct scsi_cmnd *);
int (*done)(struct scsi_cmnd *);
int (*eh_action)(struct scsi_cmnd *, int);
};
@@ -31,8 +30,5 @@ extern int scsi_register_interface(struct class_interface *);

int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req);
int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req);
-int scsi_prep_state_check(struct scsi_device *sdev, struct request *req);
-int scsi_prep_return(struct request_queue *q, struct request *req, int ret);
-int scsi_prep_fn(struct request_queue *, struct request *);

#endif /* _SCSI_SCSI_DRIVER_H */
--
1.7.10.4